RESISTANT VINES; THEIR SELECTION, ADAPTATION, ETC. 21 



the swelling is, as a rule, to be found in the acute angle formed where 

 the head joins the neck, or in other words, on the throat. There may 

 be a number of insects found on a nodosity, but the insect whose bite 

 caused the swelling will be found in this acute angle. If, however, 

 cancerous patches of decomposition are found on the more fully 

 developed roots, something more serious is threatened, namely a tuber- 

 osity. This indicates that the resistance of the vine is less than was 

 the case where only nodosities were found. Wherever tuberosities are 

 found there also are nodosities, but the reverse is not true. It is cus- 

 tomary to judge of the resistance of a vine by the nature, number, and 

 position of the tuberosities on the roots. When tuberosities are found 

 that produce only a wound, with a scab-like covering of cork, which 

 may, when dry, be scaled off with the finger-nail, there is a very 

 high resisting power; as the cancers become deeper seated and as they 

 appear more numerous on the older roots, the moare does the resisting 

 power of the vine fall. 



In order to be able to indicate with some degree of definiteness the 

 resistance to the phylloxera (not the value as a stock), an arbitrary 

 scale has been provisionally adopted by the scientists and practicians 

 of the entire viticultural world. In this scale the maximum of resist- 

 ance is taken as 20, and the minimum as 0. Thus, the resisting 

 power of the best Riparia is indicated by 19.50, and that of the Lenoir 

 (a hybrid) as 12, the best Rupestris varieties, 19.50, etc. 



From this it will be seen that the injury the phylloxera does to the 

 vine is not the loss of sap, for that is infinitesimal, but the decay of the 

 roots, thus depriving the vine of its supply of nourishment. Also, that 

 if an old, vigorous vine be attacked, it may take many years to destroy 

 the roots, they being very large and well developed; and the vine will 

 endeavor to throw out new roots as fast as the old ones become enfeebled. 

 With a young vine, on the contrary, the root-system is not large, and 

 the cancers speedily so wreck the root- system that it cannot support the 

 life of the vine. 



Examples of Resistant Standards. The importance of the fact was 

 strongly impressed upon the writer from personal observation of the 

 instance given by Prof. Pierre Viala, of the Institut Agronomique, 

 France, in his excellent work on "Adaptation." In a collection of 

 American vines at the National School of Agriculture, of Montpellier, 

 in one of the worst parts of the plot, there are, side by side, their roots 

 interlacing, some Rupestris, Solonis, Cornucopia, etc. The Rupestris 

 shows but few nodosities, no tuberosities at all, and its resistance may 

 be indicated by the figure 18 out of a possible 20. The Solonis, besides 

 a great number of nodosities, shows on the older roots a number of 

 tuberosities not very dangerous in appearance, which seldom reach as 

 far as the main roots. Its resistance is indicated by the number 15. 

 The roots of the Cornucopia are covered with large nodosities and 

 tuberosities very prominent in character, and give a resistance of 4. 



These were planted sixteen years ago. If the phylloxera were the only 

 factor in the problem, their exterior vegetation should indicate 18:15:4. 

 As a matter of fact, however, the reverse is the case. The Rupestris, 

 upon which the phylloxera causes no damage whatever, is stunted and 

 yellow and almost in a dying condition, so that its exterior vegetation 

 may be described by 2 out of a possible 20. The Solonis, although 



